Nova Velorum 1999 ( V382 Vel ) was observed by BeppoSAX 6 months after optical maximum and was detected as a bright X-ray supersoft source , with a count rate 3.454 \pm 0.002 cts s ^ { -1 } in the LECS .
It was the softest and most luminous supersoft source observed with this instrument .
The flux in the 0.1–0.7 keV range was not constant during the observation .
It dropped by a factor of 2 in less than 1.5 hour and then was faint for at least 15 minutes , without significant spectral changes .
The observed spectrum is not well fit with atmospheric models of a hot , hydrogen burning white dwarf .
This is due mainly to a supersoft excess in the range 0.1-0.2 keV , but the fit can be significantly improved at higher energy if at least one emission feature is superimposed .
We suggest that a “ pseudocontinuum ” was detected , consisting of emission lines in the supersoft X-ray range superimposed on the thermal continuum of a white dwarf atmosphere .
As a result , an accurate determination of the effective temperature and gravity of the white dwarf at this post-outburst stage is not possible .